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Stereospecific Synthesis of 2‐Oxazinyl‐4‐oxoazetidinecarbamates Starting from a 1,2‐Diazepine. A new type of intramolecular transbenzoylation
Author(s) -
Fritz Hans,
Henlin JeanMichel,
Tschamber Théophile,
Streith Jacques,
Riesen Andreas,
Zehnder Margareta
Publication year - 1988
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19880710418
Subject(s) - chemistry , intramolecular force , adduct , stereospecificity , stereochemistry , benzamide , yield (engineering) , fragmentation (computing) , catalysis , organic chemistry , materials science , metallurgy , computer science , operating system
Abstract Azeitidinodiazepines 4b and 4c react with acylnitroso dienophiles 5a–c , specifically from their convexe α‐side, but in a non‐regiospecific way, leading thereby stereospecifically to the expected adducts 6a–d and 7a–d . The three‐dimensional structures of 6a and 7a were determined by X‐ray analyses which corroborated their NMR data. OsO 4 cis ‐glycolization occurred in good yield with the inverse adducts 7a and 7e and led to the rearranged products 10 . These latter ones result from an intramolecular N‐ to O‐transbenzoylation of the short‐lived intermediates 9 followed by fragmentation of the animal function. X‐Ray analysis of 7a showed the N(10) atom to be pyramidal, a result which demonstrates that it does not have any pronounced benzamide character; otherwise no such N‐ to O‐transbenzoylation would have taken place. Structure and relative configuration of 10a were ascertained by X‐ray analysis which confirmed its NMR data as well as the stereochemical outcome of its formation.